"We received a possible threat and are taking all necessary precautions to protect the safety of our patients, employees and visitors," hospital spokeswoman Dianne Hunter told NBC Chicago at around 11:30 a.m. "It is at the recommendation of the Chicago Police Department that we are taking heightened precautions."

Police officers -- some wielding automatic weapons -- blocked the entrance to the emergency room and took up positions around the building. Police ordered pedestrians not to use the sidewalk in front of the hospital.

"I haven't seen this many machine guns since I was in the military," said Elijah Washington, who was visiting the hospital.

Some reports -- which were not confirmed by NBC Chicago -- indicated a man threatened to bring a gun to the facility.

"They said someone was inside the hospital threatening to shoot a lot of people up inside the hospital," said hospital visitor Doreatha Schaefer.

A man just called Mt Sinai Hospital and said he's headed there with his rifle to shoot the hospital up. #Chicagoland

The facility, at 1500 S. California Ave., in the city's North Lawndale neighborhood, is a Level 1 trauma center with more than 300 beds.

Published at 11:31 AM CDT on Jul 10, 2014

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